Effect of Silver Deposition on the Material Characteristics and Photocatalytic Activity of Barium Titanates

Silver (0–5 wt%) was reduced on the surface of barium titanates (BaTiO3) to investigate its effect on the properties and photocatalytic activity of the support. Samples were characterized by X-ray diffractometry, diffuse reflectance spectroscopy, photoluminescence, transmission electron microscopy, photocurrent density, and linear sweep voltammetry. Their photocatalytic activity was evaluated by phenol degradation under UV light irradiation. A commercial BaTiO3 without silver was used as a reference. Nominal silver amounts were consistent with the measured ones in the samples containing 0–3 wt% silver; however, at high nominal amounts (4–5 wt%), the measured silver content decreased significantly (~1.3 wt%). Samples containing larger silver particles had higher photoactivity than samples containing smaller silver particles. The sample containing 5 wt% silver performed the best, reaching a phenol degradation rate of 2.10 × 10−4 s−1, over an order of magnitude higher than that of the non-silver-containing reference sample (1.47 × 10−5 s−1). The enhanced photoactivity was associated with the larger silver particles covering less of the BaTiO3 surface, leaving more active sites available, and with the silver hindering charge recombination by trapping the electrons and thus increasing the efficiency of holes.